When grouping is enabled, the Views UI allows to change the thousands separator (translated: "Tausender-Trennzeichen"), e.g. from the default "," to "." or ("٬"). However, this change isn't saved.

Steps to reproduce: Run the attached view on a site with some tens of thousands of nodes, give a proper content type as argument (e.g. "songs") and Views will output something like "20,374". If you want to achieve "20.374" or "20٬374" you are out of luck.